package lmh.example.exam1_3;

import android.media.audiofx.Virtualizer;
import android.os.Bundle;
import android.Manifest;
import android.app.Activity;
import android.content.Context;
import android.content.pm.PackageManager;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.media.audiofx.BassBoost;
import android.media.audiofx.Equalizer;
import android.media.audiofx.PresetReverb;
import android.media.audiofx.Visualizer;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.LinearLayout;
import android.widget.SeekBar;
import android.widget.Spinner;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.core.app.ActivityCompat;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends Activity {

    // 定义播放声音的MediaPlayer
    private MediaPlayer mPlayer;
    // 定义系统的示波器
    private Visualizer mVisualizer;
    // 定义系统的均衡器
    private Equalizer mEqualizer;
    // 定义系统的重低音控制器
    private BassBoost mBass;
    // 定义系统的预设混响
    private PresetReverb mPresetReverb;
    private LinearLayout layout;
    private List<Short> reverbNames = new ArrayList<>();    //预设混响序号
    private List<String> reverbVals = new ArrayList<>();    //预设混响名称

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        // 设置控制音乐声音
        setVolumeControlStream(AudioManager.STREAM_MUSIC);
        layout = new LinearLayout(this);
        layout.setOrientation(LinearLayout.VERTICAL);
        setContentView(layout);
        ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.RECORD_AUDIO}, 0x123);
    }
    @Override
    public void onRequestPermissionsResult(int requestCode,
                                           @NonNull String[] permissions, @NonNull int[] grantResults)
    {
        if(requestCode == 0x123	&& grantResults[0] == PackageManager.PERMISSION_GRANTED)
        {
            // 创建MediaPlayer对象
            mPlayer = MediaPlayer.create(this, R.raw.beautiful);
            // 初始化示波器
            setupVisualizer();
            // 初始化均衡控制器
            setupEqualizer();
            // 初始化重低音控制器
            setupBassBoost();
            // 初始化预设混响
            setupPresetReverb();
            // 开始播放音乐
            mPlayer.start();
        }
    }
    // 初始化示波器的方法
    private void setupVisualizer()
    {
        // 创建MyVisualizerView组件，用于显示波形图
        final MyVisualizerView mVisualizerView = new MyVisualizerView(this);
        mVisualizerView.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.
                LayoutParams.MATCH_PARENT,
                (int)(120f * getResources().getDisplayMetrics().density)));
        // 将MyVisualizerView组件添加到layout容器中
        layout.addView(mVisualizerView);
        // 以MediaPlayer的AudioSessionId创建Visualizer
        // 相当于设置Visualizer负责显示该MediaPlayer的音频数据
        mVisualizer = new Visualizer(mPlayer.getAudioSessionId());
        mVisualizer.setCaptureSize(Visualizer.getCaptureSizeRange()[1]);
        // 为mVisualizer设置监听器
        mVisualizer.setDataCaptureListener(new Visualizer.OnDataCaptureListener()
        {

            @Override
            public void onWaveFormDataCapture(Visualizer visualizer, byte[] waveform, int samplingRate)
            {
                // 用waveform波形数据更新mVisualizerView组件
                mVisualizerView.updateVisualizer(waveform);
            }

            @Override
            public void onFftDataCapture(Visualizer visualizer, byte[] fft, int samplingRate)
            {

            }
        }, Visualizer.getMaxCaptureRate() / 2, true, false);
        mVisualizer.setEnabled(true);
    }
    // 初始化均衡控制器的方法
    private void setupEqualizer()
    {
        // 以MediaPlayer的AudioSessionId创建Equalizer
        // 相当于设置Equalizer负责控制该MediaPlayer
        mEqualizer = new Equalizer(0, mPlayer.getAudioSessionId());
        // 启用均衡控制效果
        mEqualizer.setEnabled(true);
        TextView eqTitle = new TextView(this);
        eqTitle.setText("均衡器：");
        layout.addView(eqTitle);
        // 获取均衡控制器支持的最小值和最大值
        final short minEQLevel = mEqualizer.getBandLevelRange()[0];
        short maxEQLevel = mEqualizer.getBandLevelRange()[1];
        // 获取均衡控制器支持的所有频率
        short brands = mEqualizer.getNumberOfBands();
        for (short i = 0; i < brands; i++)
        {
            TextView eqTextView = new TextView(this);
            // 创建一个TextView，用于显示频率
            eqTextView.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.
                    LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT));
            eqTextView.setGravity(Gravity.CENTER_HORIZONTAL);
            // 设置该均衡控制器的频率
            eqTextView.setText(mEqualizer.getCenterFreq(i) / 1000 + " Hz");
            layout.addView(eqTextView);
            // 创建一个水平排列组件的LinearLayout
            LinearLayout tmpLayout = new LinearLayout(this);
            tmpLayout.setOrientation(LinearLayout.HORIZONTAL);
            // 创建显示均衡控制器最小值的TextView
            TextView minDbTextView = new TextView(this);
            minDbTextView.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.
                    LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));
            // 显示均衡控制器的最小值
            minDbTextView.setText(minEQLevel / 100 + " dB");
            // 创建显示均衡控制器最大值的TextView
            TextView maxDbTextView = new TextView(this);
            maxDbTextView.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.
                    LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));
            // 显示均衡控制器的最大值
            maxDbTextView.setText(maxEQLevel / 100 + " dB");
            LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(
                    ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
            layoutParams.weight = 1f;
            // 定义SeekBar作为调整工具
            SeekBar bar = new SeekBar(this);
            bar.setLayoutParams(layoutParams);
            bar.setMax(maxEQLevel - minEQLevel);
            bar.setProgress(mEqualizer.getBandLevel(i));
            final short brand = i;
            // 为SeekBar的拖动事件设置事件监听器
            bar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener()
            {
                @Override
                public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser)
                {
                    // 设置该频率的均衡值
                    mEqualizer.setBandLevel(brand, (short)(progress));
                }

                @Override
                public void onStartTrackingTouch(SeekBar seekBar)
                {

                }

                @Override
                public void onStopTrackingTouch(SeekBar seekBar)
                {

                }
            });
            // 使用水平排列组件的LinearLayout盛装三个组件
            tmpLayout.addView(minDbTextView);
            tmpLayout.addView(bar);
            tmpLayout.addView(maxDbTextView);
            // 将水平排列组件的LinearLayout添加到myLayout容器中
            layout.addView(tmpLayout);
        }
    }
    // 初始化重低音控制器
    private void setupBassBoost()
    {
        // 以MediaPlayer的AudioSessionId创建BassBoost
        // 相当于设置BassBoost负责控制该MediaPlayer
        mBass = new BassBoost(0, mPlayer.getAudioSessionId());
        // 设置启用重低音效果
        mBass.setEnabled(true);
        TextView bbTitle = new TextView(this);
        bbTitle.setText("重低音：");
        layout.addView(bbTitle);
        // 使用SeekBar作为重低音的调整工具
        SeekBar bar = new SeekBar(this);
        // 重低音的范围为0~1000
        bar.setMax(1000);
        bar.setProgress(0);
        // 为SeekBar的拖动事件设置事件监听器
        bar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener()
        {
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser)
            {
                // 设置重低音的强度
                mBass.setStrength((short)progress);
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar)
            {
            }
            @Override
            public void onStopTrackingTouch(SeekBar seekBar)
            {
            }
        });
        layout.addView(bar);
    }
    // 初始化预设音场控制器
    private void setupPresetReverb()
    {
        // 以MediaPlayer的AudioSessionId创建PresetReverb
        // 相当于设置PresetReverb负责控制该MediaPlayer
        mPresetReverb = new PresetReverb(0, mPlayer.getAudioSessionId());
        // 设置启用预设音场控制
        mPresetReverb.setEnabled(true);
        TextView prTitle = new TextView(this);
        prTitle.setText("音场");
        layout.addView(prTitle);
        // 获取系统支持的所有预设音场
        for (short i = 0; i < mEqualizer.getNumberOfPresets(); i++)
        {
            reverbNames.add(i);
            reverbVals.add(mEqualizer.getPresetName(i));
        }
        // 使用Spinner作为音场选择工具
        Spinner sp = new Spinner(this);
        sp.setAdapter(new ArrayAdapter<>(MainActivity.this,
                android.R.layout.simple_spinner_item, reverbVals));
        // 为Spinner的列表项选中事件设置监听器
        sp.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener()
        {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id)
            {
                // 设定音场
                mEqualizer.usePreset(reverbNames.get(position));
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent)
            {
            }
        });
        layout.addView(sp);
    }
    @Override public void onPause()
    {
        super.onPause();
        if (isFinishing() && mPlayer != null)
        {
            // 释放所有对象
            mVisualizer.release();
            mEqualizer.release();
            mPresetReverb.release();
            mBass.release();
            mPlayer.release();
            mPlayer = null;
        }
    }

    private static class MyVisualizerView extends View
    {
        // bytes数组保存了波形抽样点的值
        private byte[] bytes;
        private float[] points;
        private Paint paint = new Paint();
        private Rect rect = new Rect();
        private byte type = 0;

        public MyVisualizerView(Context context)
        {
            super(context);
            // 设置画笔的属性
            paint.setStrokeWidth(1f);
            paint.setAntiAlias(true);
            paint.setColor(Color.GREEN);
            paint.setStyle(Paint.Style.FILL);
        }


        public void updateVisualizer(byte[] ftt)
        {
            bytes = ftt;
            // 通知该组件重绘自己
            invalidate();
        }

        @Override
        public boolean onTouchEvent(MotionEvent me)
        {
            // 当用户触碰该组件时，切换波形类型
            if (me.getAction() != MotionEvent.ACTION_DOWN) {
                return false;
            }
            type++;
            if (type >= 3) {
                type = 0;
            }
            return true;
        }

        @Override
        protected void onDraw(Canvas canvas)
        {
            super.onDraw(canvas);
            if (bytes == null) {
                return;
            }
            // 绘制白色背景（主要为了印刷时好看）
            canvas.drawColor(Color.WHITE);
            // 使用rect对象记录该组件的宽度和高度
            rect.set(0, 0, getWidth(), getHeight());
            switch (type) {
                // -------绘制块状的波形图-------
                case 0:
                    for (int i = 0; i < bytes.length - 1; i++) {
                        float left = (getWidth() * i / (bytes.length - 1));
                        // 根据波形值计算该矩形的高度
                        float top = rect.height() - (byte) (bytes[i + 1] + 128) * rect.height() / 128;
                        float right = left + 1;
                        float bottom = rect.height();
                        canvas.drawRect(left, top, right, bottom, paint);
                    }
                    break;
                // -------绘制柱状的波形图（每隔18个抽样点绘制一个矩形）-------
                case 1:
                    for (int i = 0; i < bytes.length - 1; i += 18) {
                        float left = rect.width() * i / (bytes.length - 1);
                        // 根据波形值计算该矩形的高度
                        float top = rect.height() - (byte) (bytes[i + 1] + 128)
                                * rect.height() / 128;
                        float right = left + 6;
                        float bottom = rect.height();
                        canvas.drawRect(left, top, right, bottom, paint);
                        i += 18;
                    }
                    break;
                // -------绘制曲线波形图-------
                case 2:
                    // 如果points数组还未初始化
                    if (points == null || points.length < bytes.length * 4) {
                        points = new float[bytes.length * 4];
                    }
                    for (int i = 0; i < bytes.length - 1; i++)
                    {
                        // 计算第i个点的x坐标
                        points[i * 4] = rect.width()*i/(bytes.length - 1);
                        // 根据bytes[i]的值（波形点的值）计算第i个点的y坐标
                        points[i * 4 + 1] = (rect.height() / 2)
                                + ((byte) (bytes[i] + 128)) * 128
                                / (rect.height() / 2);
                        // 计算第i+1个点的x坐标
                        points[i * 4 + 2] = rect.width() * (i + 1)
                                / (bytes.length - 1);
                        // 根据bytes[i+1]的值（波形点的值）计算第i+1个点的y坐标
                        points[i * 4 + 3] = (rect.height() / 2)
                                + ((byte) (bytes[i + 1] + 128)) * 128
                                / (rect.height() / 2);
                    }
                    // 绘制波形曲线
                    canvas.drawLines(points, paint);
                    break;
            }
        }
    }
}
